1. Field of the Invention
This invention relates to thermally responsive controls for use in refrigeration apparatus and the like and more specifically to temperature sensing detectors for use in such controls.
2. Description of the Prior Art
In controlling refrigeration apparatuses, such as refrigerators, freezers, air conditioners, and the like, it is conventional to utilize temperature sensing detectors providing an automatic control of the operation of the apparatus to provide the desired refrigeration conditions. It has further been known to embed the temperature sensing detector within an enclosing means so as to affect the thermal transfer to the temperature sensing detector in different manners. Thus, illustratively, Bobby D. Blanton et al, in U.S. Pat. No. 3,899,895, show an automatic defrosting control system wherein a thermal relay having a thermally responsive actuating disc is enclosed within a housing including an inner heat sink formed of metal, such as cooper, acting as a thermal reservoir or capacitor, and an outer block of thermal insulation, such as foamed polyurethane.
Another fluid flow detection apparatus is shown in the Edmond A. Salera patent No. 3,199,348 wherein a semiconductor temperature sensor embedded in a glass envelope is further embedded in a thermally semiconductive and electrically insulative material in a cavity defined by a body of heat insulating material, such as ceramic or a plastic, such as epoxy-type resin containing pieces of cork or like highly heat insulative material.
Luther J. Jungemann discloses, in U.S. Pat. No. 3,158,005, owned by the assignee hereof, a structure for providing improved temperature sensing in a refrigeration apparatus, such as an air conditioner, the embedment of the temperature sensing detector in a block of material having limited thermal conductivity, such as a GRS type rubber compound, or neoprene rubber with metallic powder, such as aluminum or zinc oxide, dispersed therein.